Machine tools are used to manufacture parts by a cutting process using a variety of implements such as cutting tools, electrodes or lasers. Machine tools may be manually operated, mechanically automated, or digitally automated via computer numerical control (CNC). One type of machine tool is a tube-cutting machine for cutting long and thin tubes on a small scale.
Production of tubes for biomedical applications such as marker band and stent applications requires strict process quality, including incoming material quality, such as raw tube diameter, raw tube wall thickness, etc., and finished part dimensions, such as cut tube diameter, cut tube wall thickness, and cut tube length, for example.
Generally, the raw tube is fragile (as its shape is typically long and thin) and can be damaged during the handling process loading the tube into the cutting machine, as well as in the feeding mechanism inside the cutting machine. As a result, measuring the quality of the raw tubes before they are loaded into the machine is not sufficient to ensure overall quality. The raw tube quality is typically desired to be validated immediately prior to the cutting process to ensure no damage has occurred up-stream from the cutting process. However, if the raw tube quality cannot be measured in this way, then the finished parts must be measured down-stream from the cutting process.
In addition, the finished (cut) parts are generally small (e.g., with diameters typically between 0.010″ and 0.250″ and length-to-diameter ratios of roughly 1:1) and therefore these parts tend to be difficult to handle. As a result, validating the finished part quality by measuring after the cutting process has taken place is challenging.
Older generations of lasers used in tube cutting systems produced a rough cut-edge, making inspection during or directly after the cut impractical. Instead, the cut pieces first had to be cleaned (de-burred, tumbled, washed, etc.) before measurements could be taken. The latest generation of lasers used in tube cutting systems produce a clean cut-edge, making inspection during or directly after the cut practical.